Formation-sampling apparatus



D United States Patent 1111 3,550, 99

[72] Inventor C P Lanmon ll [56] References Cited Friendswwd- UNITED STATES PATENTS P 3,085,636 4/1963 Bennett et al 175/77 [22] F1led Nov. 29,1968

3,136,376 6/1964 Roblnsky... l75/3l8 meme 3 154 157 10/1964 A 1 1 l75/78 73] Assignee Schlumberger Technology Corporation n e son I 3,430,7l6 3/1969 Urbanosky l75/78 New York, N.Y. a corporation of Texas Primary Examiner-David H. Brown Attorneys-Ernest R. Archambeau, Jr., William J. Beard,

David L. Moseley, Edward M. Roney, William R. Sherman and Stewart F. Moore ABSTRACT: The particular embodiment described herein as illustrative of the invention is directed to formation-sampling [54] fggmfi ggfiax gg APPARATUS apparatus for more reliably collecting one or more samples of 8 earth formations traversed by a borehole. To accomplish this, [52] U.S. Cl. 175/78, the disclosed borehole apparatus includes selectively operable 175/311 closure means adapted for preventing the loss of a sample [Sl] lnt.Cl. E2lb49/02 once it is collected as well as for blocking the entrance of [50] Field of Search 175/76- foreign matter as the apparatus is being moved through a mea r borehole.

PAIENTED 050291970 FIG. 28

CP Lcmmon,II

INVENTOR WM d A T TORNE Y FORMATION-SAMPLING APPARATUS Various tools have recently been introduced to the oil industry for obtaining elongated samples of earth formations traversed by a borehole. For example, tools such as those shown in US. Pat. No. 3,173,500 and U.S. Pat. No. 3,405,772 have been proposed for obtaining single samples of a substantial length. In these tools, a pair of rotatable, outwardly converging cutting wheels are arranged to be extended outwardly through an elongated opening in the tool housing and cut their way into an adjacent formation. Then, as either the entire tool or the cutting wheels are slowly raised, a single elongated wedge-shaped formation sample is cut out of the borehole wall. This individual sample is caught by the tool and returned to the surface. On the other hand, new and improved repetitively operabletools such as those shown in US Pat. No. 3,430,716 and a copending application Ser. No. 765,383 by Harold J. Urbanosky owned by the present assignee have also been proposed forsuccessively collecting a plurality of such elongated formation samples during a single trip into a borehole. These tools also employ a pair of convergent cutting wheels that are selectively extended and moved longitudinally discontinuous nature of most, if not all, earth formations will often preclude the recovery of integral or unbroken samples ture such irregular formation segments are frequently washed out or displaced from thesample receiver and often lost through the elongated opening in the housing during subsequent movements of the tool through the borehole. Moreover, it has been found that as such tools are moved along a well bore-containing mud, loose debris and the like, such unwanted foreign matter will tend to accumulate in the tool and frequently cause jamming of some of its movable elements. In either case, the sampling operation will, of course,

be partially or totally unsuccessful.

Accordingly, it is an object of the present invention to provide new and improved formation-sampling apparatus for collecting one or more elongated samples of earth formations traversed by a borehole and having means for reliably retaining these samples as well as blocking the entrance of unwanted foreign matter that might impair the successful operation of the apparatus.

This and other objects of the present invention are attained by providing formation-sampling apparatus with formationcutting means adapted to be selectively extended through an elongated opening in a housing for collecting one or more samples from selected earth formations. To prevent loss of previously collected samples as well as to block the entrance of foreign matter through the access opening while the apparatus is being positioned, the formation-sampling apparatus further includes means for selectively blocking or closing the access opening so long as the apparatus .is not collecting a sample. I

The novel features of the present invention are set forth with particularity in the appended claims. The inventiontogether with further objects and advantages thereof, may be best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, in which:

FIG. 1 depicts an exemplary formation-sampling tool arranged in accordance with the present invention and in position in a borehole to obtain a formation sample;

FIG. 4 shows the forward face of a portion of the tool depicted in FIG. 2.

Turning now to FIG. 1, a formation-sampling tool 10, including selectively operable closure means 11 arranged in accordance with the present invention, is shown suspended from a cable 12 in a borehole 13 and in position for formation-collecting means, such ,as a pair of converging similar cutting wheels 14, to selectively remove an elongated sample 15 from the exposed face of an earth formation 16 for deposit in a sample receiver 17 therebelow. Suitable circuitry 18 (such as described in a copending application, Ser. No. 649,978 filed Jun. 29, 1967) is provided for locating the tool 10 at a desired position in the borehole 13 as well as for controlling the tool from the surface by way of electrical conductors in the suspension cable 12.

A pair of pistons 19 are operatively arranged for selectively extending a wall-engaging anchor 20 from the rear of the tool 10 against one side of the borehole 13 to laterally shift the sampling tool in the opposite direction. To actuate the wall engaging member 20 from the surface, a pump 21 is arranged to selectively pump hydraulic fluid into piston chambers either behindor ahead of the pistons 19. By maintaining an increased hydraulic pressure behind the pistons 19, the anchor .20 will, therefore, urge the forward face of the tool 10 against the opposite wall of the borehole 13 with sufficient force to anchor the tool in a selected position .as the cutting wheels 14 are being operated.

The cutting wheels 14 are mounted in converging vertical planes and rotatively driven about outwardly diverging axes lying generally in the same horizontal plane. The peripheral edges'of the cutting wheels 14 all but intersect so that, when extended and selectively moved upwardly through an elongated, fairly narrow, longitudinal access opening 22 provided in the forward wall of the tool housing 23, the rotating wheels will cut away a generally wedge-shaped or triangular prismatic sample (as at 15) from the adjacent face of the formation 16.

The receiver 17 in the lowermost portion of the tool 10 includes means for reliably segregating a selected number of formation samples from one another. Asdescribed in the Urbanosky patent mentioned above, in one manner of arranging the sample receiver 17 a plurality of upright tubes are sequentially positioned to respectively receive successively collected formation samples as the tool 10 is operated. As an alternate, the sample receiver 17 can also be arranged as described in the above-mentioned Urbanosky application. In this latter arrangement, a plurality of upright partitions or transverse dividers (not shown in FIG. 1) are uniquely arranged for'selectively isolating the formation samples as they are collected. In either instance, therefore, the tool 10 can be efficiently employed on a single trip in the borehole 13 to recover one or more formation samples that will be individually segregated in the sample receiver 17 in predetermined positions.

Turning now to FIGS. 2A and 23, a somewhat schematic representation is shown of a preferred embodiment of the tool 10 including the present invention. As seen in FIG. 2A, the cutting wheels 14 are dependently carried by a longitudinally movable enclosure 24 having a pair of upright tubular members 25 (only one shown) mounted along its rear wall and slidably disposed about substantially longer rods 26 (only one shown) securedat theirupper and lower ends and extending longitudinally adjacent to the rear wall of the tool housing 23. The opposite ends of the tubular members 25 are slidably sealed around these rods 26 and a-piston member 27 (only one shown) is fixed at an intermediate position on each of the elongated rods to define separate fluid-tight chambers 28 and 29 within the internal bore of its associated tubular member.

FIGS. 2A and 2B are successive views schematically illus- I of FIG. 2A; and

Accordingly, by developing a higher fluid pressure in the upper chambers 28 than that in the lower chambers 29, the enclosure 24 will be moved longitudinally upwardly along the elongated rods 26 in relation to the stationary tool housing 23. Similarly, by imposing a higher pressure in the lower chambers 29, the enclosure 24 will travel longitudinally downwardly along the rods 26. A suitable hydraulic pump 30 is mounted within the enclosure 24 and appropriately arranged to selectively pump hydraulic fluid to the chambers 28 and 29 upon command from the surface as required to shift the enclosure back and'forth along the elongated rods 26.

An'electric motor 31 in the enclosure 24 is operatively connected by a universal joint to a right-angle gear drive 32 having outwardly diverging shafts for rotatively driving the cutting wheels. A pair of depending arms, as at 33, are pivotally connected at their upper ends to the motor enclosure 24 for supporting the gear drive 32 secured to their lower ends.

To operatively position the cutting wheels 14, outwardly biased guide pins 34 (only one shown) mounted near the lower ends of each of the pivoted arms 33 are slidably disposed in a system of guide grooves 35 (only one system shown) formed in the interior sidewalls of the tool housing 23 on opposite sides of the longitudinal opening 22 therein. These groove systems 35 are arranged so that upward travel of the motor enclosure 24 from its full-line position to its dashedline position will be effective (through the coaction of the guide pins 34 in their respective groove systems) to direct the cutting wheels 14 along an established path. Thus, once the housing enclosure 24 is shifted upwardly a short distance, the groove systems 35 will guide the cutting wheels 14 along the path A-B-C-D for cutting away a prismatic sample, as at 15, with tapered ends from the formation 16 for subsequent deposit in the core receiver 17 therebelow. Then, shortly after the cutting wheels 14 are retracted (position D"), the enclosure 24 is halted in its uppermost position as illustrated. When the enclosure 24 is subsequently returned downwardly from its uppermost position, the groove systems 35 are preferably arranged so that the rotating cutting wheels 14 are passed downwardly back through their respective kerfs which they had previously cut into the formation 16 for dislodging the formation sample should it still be in the complementary cavity cut into the formation.

As seen in FIG. 2B, a plurality of upright transverse dividers 36-38 in the sample receiver 17 are selectively positioned in response to the cyclical upward and downward movements of the motor enclosure 24 for successively segregating the formation samples once they pass through a sample passage 39 communicating the access opening 22 with the upper end of the receiver. To accomplish this, the dividers 36-38 are initially positioned along the rear wall of the housing 23 and releasably retained in this position by a somewhat U-shaped latch 40 arranged for controlled vertical travel relative thereto. Thus, when the first formation sample is cut away by the cutting wheels 14, it will pass through the housing opening 22 and passage 39 and come to rest on the forward face of the first divider 36.

As described in more detail in the above-mentioned Urbanosky application, to successively release the dividers in response to subsequent cyclical operations of the tool 10, the upper ends of the dividers 36-38 are reduced in width, as at 4l43, at progressively higher points. By progressively moving the U-shaped latch 40 upwardly to each of these shoulders 41-43 in turn, a number of U-shaped springs, as at 44, respectively biasing the dividers 36-38 will sequentially shift the reduced upper ends of the dividers forwardly between the inwardly turned opposed fingers 45 of the latch. Thus, although upward travel of the latch 40 will ultimately release all of the dividers 36-38, only one divider will be released at a time and the other dividers will be retained against the rear wall of the housing 23 until the latch has been shifted further upwardly by subsequent operations of the tool 10.

To control the longitudinal travel of the latch 40, a vertical spindle shaft 46 is journaled between longitudinally spaced bearings 47 and 48 mounted on the rear wall ofthe housing 23 just below the latch. A somewhat resilient cam follower 49 dependently secured to the latch 40 is extended downwardly alongside the spindle 46 and cooperatively guided by a system of zig-zagged or alternating cam grooves 50 formed around the rotatable spindle and providing progressively higher cam stops (not shown) respectively spaced to correspond with the progressively higher shoulders 41-43 on the dividers 36-38.

As fully described in the above-mentioned Urbanosky application, the alternating cam-guiding system 50 includes a plurality of circumferentially spaced longitudinal grooves having their upper ends located at progressively higher positions on p the vertical spindle 46 to provide the above-mentionedca rri stops and a plurality of downwardly inclined grooves respectively interconnecting the .upper end of each longitudinal groove to the lower end ofthenext adjacent and higher lonthe lower end of the lowermost longitudinal groove. Shoulders I are appropriately located across the exit of each' of the grooves on the spindle 46 to assure that the cam follower 49 will progressively move around the spindle along the zigzagged path 50.

it will be appreciated, therefore, that successive reciprocating movements of the latch 40 will progressively shift its depending cam follower 49 on through the spindle grooves 50 to progressively halt the latch at a successively higher elevation as determined by the upper ends of the longitudinal spindle grooves. Accordingly, by spacing the divider shoulders 41- 43 to correspond with the vertical spacing of the cam stops on the spindle 46, successive reciprocations of the latch 40 will sequentially release the dividers 36-38 as the latch is progressively raised above the shoulders.

To selectively reciprocate the latch in response to the cyclical operations of the sm sample-collecting means 14, an upright actuating member 51 is secured to the latch and slidably guided for vertical reciprocation along the rear wall of the housing 23. An actuator rod 52 depending from the motor enclosure 24 (FIG. 2A) is provided with an enlarged lower end 53 that is adapted to be selectively received by a plurality of upwardly extending yieldable collet fingers 54 on the upper end of the actuating member 51.

Accordingly, upon initial upward travel of the enclosure 24, the actuator rod 52 will pull the depending cam follower 49 (as well as the actuating member 51 and latch 40)'a short distance upwardly until it is halted by contacting the top of the longitudinal spindle groove it is then in. Once these members are halted, the continued upward travel of the enclosure 24 will retract the enlarged rod head 53 from the yieldable collet fingers 54 and friction will retain the latch 40 in its elevated position. Then, when the motor enclosure 24 is subsequently returned downwardly the enlarged rod head 53 will again con tact the collet 54 and push the actuating member 51 downwardly until it is halted when the cam follower 49 reaches the bottom of the next adjacent longitudinal spindle groove. Once the actuating member 51 is halted, continued downward travel of the motor enclosure 24 toward its final position will push the enlarged rod head 53 back into engagement with the collet fingers.

It will be appreciated, therefore, that the unique arrangement of the sampling tool 10 will permit multiple formation samples to be successively collected and reliably segregated in the receiver 17 for subsequent recovery and examination at the surface. As previously mentioned, however, there is always the dual risk that movement of the tool 10 through the borehole 13 will divert unwanted foreign matter into the tool as well as cause one or more portions of a previously collected sample to be lost through the access opening 22.

For example, it is not at all uncommon for even fairly large pieces of metal, rubber, and other sundry foreign objects to be suspended in the usually dense and frequently viscous control placed around the sides of the tool. Moreover, without the present invention, each time the forward face of the tool 10 was urged laterally against a borehole wall, so-called "mud cake as well as loose formation materials and the like would readily enter the longitudinal access opening 22 in the housing 23. Similarly, downward movement of the tool through the borehole 13 will tendto divert what may well be a substantial flow of borehole fluids upwardly through various drain openings and the like in the sample receiver 17. Without the present invention, this upward flow of fluids through the sample receiver 17 has often been found to besufficient to displace one or more formation fragments as at 55 out of the receiver and through the access opening 22.

It will be appreciated, therefore, that if the access opening 22 is closed, these problems can be relieved, if not eliminated altogether. On the other hand, the access opening 22 must, of course, be opened whenever the cutting wheels 14 are moving longitudinally. Accordingly, in keeping with the objects of the present invention, the selectively operable closure means 11 are operatively arranged to fully close the longitudinal opening 22 so long as the cutting wheels 14 are not being operated.

In the preferred manner of accomplishing this, therefore, as seen in FIG. 3, the motor enclosure 24 isappropriately positioned and sized in relation to the housing 23'that the forward face of the enclosure is substantially tangential or concyclic with the internal curvature of the forward wall of the housing. By minimizing the width of the longitudinal opening 22, the clearance between the inside corners of opening and the forward surface of the motor enclosure 24 is so limited that no debris of any significant size can enter these narrow gaps. Similarly, as seen in FIG. 2, the housing enclosure 24 is purposely arranged to extend above the upper end of the elongated opening 22.

Thus, the only significant exposure remaining when the motor enclosure 24 is in its lowermost position is the lower portion of the access opening 22. It will be appreciated, of course, that the lower end of the motor enclosure 24 could be extended below the lower end of the opening 22 when the motor enclosure was in its lowermost position. Although this would satisfactorily block the lower end of the access opening 22 in the same manner as the upper end of the opening is blocked, this would require that the cutting wheels 14 travel further upwardly before they reach'their position at A and consequently lengthen the tool 10 somewhat. Accordingly, the selectively operable closure means 11 are further comprised of a closure member 56 dependently secured from the forward face of the motor enclosure 24 and cooperatively arranged for matching association with either a separate upright member, as at 57, secured to the housing 23 across the lower portion of the opening 22 or to that part of the housing defining the lower portion of the longitudinal access opening. It will be appreciated, therefore, that by complementally curving the depending member 56 to conform to the internal wall of the housing, the closure member will be correspondingly moved as the motor enclosure 24 is selectively shifted upwardly and downwardly to collect a formation sample. Moreover, by forming the depending closure. member 56 from relatively thin material, it can be readily fitted into he annulus between the housing 23 and motor enclosure 24 without affecting their dimensions. v

As best seen, in FIG. 4, therefore, the depending closure member 56 is at least slightly wider than the width of the longitudinal opening 22 and has its lower end terminated sufficiently above the cutting wheels 14 so as not to interfere with their lateral extension. The upright closure member 57 is carried upwardly a sufficient distance to at least slightly overlap the lower end of the depending closure member 56 when the motor enclosure 24 isin its lowermost position in relation to the housing 23.

Accordingly, it will be appreciated that upward travel of the motor enclosure 24 will carry the depending closure member 56 upwardly in relation to the stationary housing 23. As the lower end of the moving closure member 56 clears thelower portion 57 of the lower end of the opening 22, the upward travel of the motor enclosure 24 will progressively extend the cutting wheels 14 upwardly and outwardly (positions "A" to B"). If needed, clearance may be provided for the lower portion of the wheels 14 by forming an upwardly diverging notch, as at 58, in the upper end of the fixed closure member 57. Thus, once the cutting wheels, 14 are fully extended (position B"), they will begin collecting a formation sample, as at 15, during the course of the upward travel of the motor enclosure 24.

Once the motor enclosure 24 has reached its upper limit of travel and is returned downwardly, the reverse action will be repeated but in the opposite direction. Thus, once the downwardly moving enclosure 24 hasagain brought the lower end of the depending closure member 56 into association with the upright member 57, the cutting wheels 14 will be fully retracted and the longitudinal opening 22 will again be substantially blocked. I

Accordingly, it will be recognized that the upward and downward travel of the motor enclosure 24 will be effective to selectively open and close the longitudinal opening 22 as far as is practical without limiting the operation of the tool 10. In

this manner, whenever the cutting wheels 14 are operatively I collecting a formation sample, the closure means 11 of the present invention will progressively open the access opening as the operation continues. On the other hand, the closure means 11 are effective to close the opening 22 when most needed to prevent the loss of formation samples from the receiver 17 as well as the unwanted entrance of foreign matter and debris from the borehole fluids. Thus, if a fragment of a sample, as at 55, is inadvertently displaced upwardly into the sample passage 39, the fragment cannot be displaced out of the sample receiver 17 and be lost through the opening 22.

Accordingly, although changes and modifications may be made in the disclosed embodiment without departing from the principles of the present invention as defined in the appended claims, it will be appreciated that the present invention provides new and improved means for reliably collecting samples of earth formations traversed by a borehole. By substantially closing the only major opening in the housing, sample fragments that might otherwise become inadvertently displaced therefrom during movement of the sampling apparatus are fully enclosed by the closure means of the present invention. Moreover, debris is prevented from entering the apparatus as it is moved through a well bore.

Iclaim: I

1. Apparatus adapted for obtainingsamples of earth formations traversed by a borehole and comprising: a tubular support adapted for suspension in a borehole and having an opening therein providing access to the interior of said support; formation-sampling means operatively arranged'within said support for movement therein through said access opening to an extended position for procuring formation samples exterior of said support; and closure means normally blocking said access opening operatively coupled to said formation-sampling means and movable thereby upon movement of said formation-sampling means toward said extended position for uncovering said access opening.

2. The apparatus of claim 1 wherein said formation-sampling means are selectively movable from said exterior position back to a retracted position and said closure means are movable thereby upon movement of said formation-sampling means back to said retracted position for again blocking said access opening.

3. Apparatus adapted for obtaining samples of earth formations traversed by a borehole and comprising; a tubular support adapted for suspension in a borehole and having an elongated opening extending longitudinally along one wall of said support providing access to the interior of said support; formation-sampling means operatively arranged within said support for longitudinal travel therein, said formationsampling means including formation-cutting means adapted for lateral movement from a normally retracted position within said support through said access opening to an extended position exterior of said support; means adapted for moving said formationcutting means toward; said extended position upon travel of said formation-sampling means; and closure means normally covering said access opening and operatively coupled to said formation-sampling means and movable thereby for uncovering said access opening upon movement of said formationcutting means toward said extended position.

4. The apparatus of claim 3 wherein said closure means are movable upon return movement of said formation-cutting means from said extended position to said normally-retracted position for recovering said access opening whenever said formation-cutting means have returned to said normallyretracted position 5. Apparatus adapted for obtaining samples of earth formations traversed by a borehole and comprising: a tubular support adapted for suspension in a borehole and having an elongated opening extending longitudinally along one wall of said support providing access to the interior of said support; formation-cutting means operatively arranged within said support for travel relative thereto between longitudinally spaced positions; means responsive to travel of said formation-cutting means for progressively directing said formation-cutting means outwardly from within said interior of said support through said access opening to the exterior of said support and then returning said formation-cutting means to said interior of said support; and means normally blocking said access opening and operable upon travel of said formation-cutting means for progressively uncovering said access opening as said formation-cutting means are progressively directed therethrough.

6. Apparatus adapted for obtaining samples of earth formations traversed by a borehole and comprising: a tubular support adapted for suspension in a borehole and having an elongated opening extending longitudinally along one wall of said support providing access to the interior of said support; formation-cutting means operatively arranged within said support for travel relative thereto between first and second longitudinally spaced positions; means responsive to travel of said formation-cutting means for progressively directing said formation-cutting means outwardly from within said interior of said support through said access opening to the exterior of said support as said formation-cutting means move away from said first position and then returning said formation-cutting means back into said interior of said support as said formation-cutting means approach said second position; and closure means normally blocking said access opening so long as said formation-cutting means are in said first position and responsive to travel thereof toward said second position for progressively uncovering said access opening ahead of said formationcutting means.

7. The apparatus of claim 6 wherein said closure means are responsive to travel of said formation-cutting means back to said first position for progressively recovering said access opening.

8. The apparatus of claim 7 wherein said directing means are also responsive to travel of said formation-cutting means back to said first position for progressively directing said formation-cutting means back outwardly from within said interior of said support as said formation-cutting means move away from said second position and then returning said formationctting means back into said interior of said support as said formation-cutting means again return to said first position.

9. Apparatus adapted for obtaining samples of earth formations traversed by a borehole and including: a tubular housing adapted for suspension in a borehole and having a longitudinal opening along one wall of said housing providing access to the interior thereof; a support disposed within said housing and through said access opening to the exterior of said housingl as said support moves away from its said first position and t en returning said cutting wheels back through said access opening into said interior of said housing as said support approaches its said second position; and closure means on said support normally blocking said access opening so long as said support is in its said first position and responsive to travel thereof toward its said second position for progressively uncovering said access opening ahead of said cutting wheels.

10. The apparatus of claim 9 wherein said closure means are adapted for reblocking said access opening upon return of said support to its said first position.

11. The apparatus of claim 9 wherein said closure means are responsive to return movement of said support back toward its said first position for progressively recovering said access opening and again blocking said access opening when said support has again reached its said first position.

12. The apparatus of claim 9 wherein said closure means include a plate projecting longitudinally from one end of said support and complementally fitted adjacent to said one housing wall for covering the adjacent portion of said access openmg.

13. The apparatus of claim 9 wherein said guide means are operable upon return movement of said support back toward its said first position for again extending said cutting wheels outwardly through said access opening to the exterior of said housing as said support moves back from its said second position and then returning said cutting wheels back through said access opening into said interior of said housing as said support approaches its said first position.

14. The apparatus of claim 13 wherein the return path of said cutting wheels as said support is returned from its said second position to its said first position is identical to the path followed by said cutting wheels as said support is moved from its said first position to its said second position.

15. The apparatus of claim 13 wherein said closure means are responsive to return movement of said support back toward its said first position for progressively recovering said access opening behind said cutting wheels and again blocking said access opening when said cutting wheels are retracted and said support has again reached its said first position.

16. The apparatus of claim 15 wherein the return path of said cutting wheels as said support is returned from its said second position to its said first position is identical to the path followed by said cutting wheels as said support is moved from its said first position to its said second position. 

